Hmm. The only thing I can think happened is when they set up your broadband account, they set it up for areas references 20-22, where it was billed and controlled seperately to everything else.
In areas 24-31 it is billed with all other services, but used to be controlled seperately.
When you highlighted the error on the billing, they shut the whole account down, rather than converting it to a control only account. This is why your modem stopped working and why your e-mail addresses have disappeared.
Some changes to systems have been made over the last month and a half. This now means e-mail address are not required to set up modems, so this is why the e-mail address have not been reactivated. For what it is worth, it also means this can never happen again!
However, why technical support cannot manually reactivate them, I do not know
Customer Care cannot do anything as they have no access to the technical aspects of the account. They cannot see, add, remove or change any e-mail address or password. They can only see the billing of your services.
P.S. Newgroup access is not dependent on OS, just on the program you use
http://www.newsreaders.com/unix/clients.html